State-run Saudi Aramco's project will involve building
processing facilities, wellheads and pipelines for the gas in
Turaif in the northern part of Saudi Arabia where the big mining
project Waad al-Shamal is under development, the sources said.

Saudi Aramco, SNC-Lavalin, JGC and GS declined to comment,
while Maire Tecnimont was not available for comment.

The search for gas has been a priority for Saudi Arabia as
it struggles to keep pace with rapidly rising domestic demand.

Aramco plans to produce as much as 200 million cubic feet
per day of unconventional natural gas by 2018 to supply the Waad
al-Shamal project and a power plant.

Inspired by a shale gas surge in the United States, which
has transformed it from the world's largest gas importer to an
exporter, Saudi has begun investigating its large unconventional
gas reserves.

The kingdom has made appraisals in the northwest area, the
Eastern Province and in the Empty Quarter, but the hunt is yet
to prove fruitful.

Saudi Arabia, which holds the world's fifth-largest proven
reserves of gas, expects domestic demand for natural gas - which
it uses mainly for power generation - almost to double by 2030
from 2011 levels of 3.5 trillion cubic feet per year.

Saudi Oil Minister Ali al-Naimi had estimated the country's
unconventional gas reserves - those held in reservoirs that have
not been traditionally exploited - at over 600 trillion cubic
feet, more than double its proven conventional reserves.

Aramco Chief Executive Khalid al-Falih has said Riyadh will
spend $3 billion on shale gas development in the kingdom but has
given no details on the investment.
(Reporting by Reem Shamseddine; Additional reporting by Yuka
Obayashi,; Solarina Ho,; Francesca Landini and Joyce Lee;
Editing by Rania El Gamal and Dale Hudson)